This invention relates to apparatus and method for implanting a conduit to allow communication of fluids from one portion of a patient""s body to another; and, more particularly, to a blood flow conduit to allow communication from a heart chamber to a vessel or vice versa, and/or vessel to vessel. Even more particularly, the invention relates to a left ventricular conduit and related conduit configurations for controlling the flow of blood through the conduit to achieve bypass of a stenosed or occluded coronary artery.
Coronary artery disease is a major problem in the U.S. and throughout the world. Coronary arteries as well as other blood vessels frequently become clogged with plaque, which at the very least impairs the efficiency of the heart""s pumping action, and can lead to heart attack, arrhythmias, and death. In some cases, these arteries can be unblocked through noninvasive techniques such as balloon angioplasty. In more difficult cases, a bypass of the blocked vessel is necessary.
In a bypass operation, one or more venous segments are inserted between the aorta and the coronary artery. The inserted venous segments or transplants act as a bypass of the blocked portion of the coronary artery and thus provide for a free or unobstructed flow of blood to the heart. More than 500,000 bypass procedures are performed in the U.S. every year.
Such coronary artery bypass surgery, however, is a very intrusive procedure that is expensive, time-consuming and traumatic to the patient. The operation requires an incision through the patient""s sternum (sternotomy), and that the patient be placed on a bypass pump so that the heart can be operated on while not beating. A vein graft is harvested from the patient""s leg, and a delicate surgical procedure is required to piece the bypass graft to the coronary artery (anastomosis). Hospital stays subsequent to the surgery and convalescence are prolonged. Furthermore, many patients are poor surgical candidates due to other concomitant illnesses.
As mentioned above, another conventional treatment is percutaneous transluminal coronary angioplasty (PTCA) or other types of angioplasty. However, such vascular treatments are not always indicated due to the type of location of the blockage or stenosis, or due to the risk of emboli.
Thus, there is a need for an improved bypass system that is less traumatic to the patient.
The preferred embodiments of the present invention address the need in the previous technology by providing a bypass system that avoids the sternotomy and other intrusive procedures normally associated with coronary bypass surgery. These embodiments also free the surgeon from the need to perform multiple anastomoses as is necessary in the current process.
The preferred device provides a conduit or shunt for diverting blood directly from the left ventricle of the heart to a coronary artery, at a point distal to the blockage or stenosis, thereby bypassing the blocked portion of the vessel. The conduit preferably comprises a tube adapted to be positioned in the myocardium and having a one way valve therein. The valve prevents the backflow of blood from the coronary artery into the left ventricle.
The conduit device is delivered through the coronary artery to a position distal the blockage or stenosis. At that position, the coronary artery, the myocardium and the wall of the left ventricle are pierced to provide an opening or channel completely through from the coronary artery to the left ventricle of the heart. The conduit is then positioned in the opening to provide a permanent passage for blood to flow between the left ventricle of the heart and the coronary artery, distal to the blockage or stenosis. The conduit is sized so that one open end is positioned within the coronary artery, while the other open end is positioned in the left ventricle. The hollow lumen of the conduit provides a passage for the flow of blood.
To prevent the backflow of blood from the coronary artery to the left ventricle of the heart, the conduit is provided with a one-way valve. The valve is preferably a windsock type valve, a flapper valve, a bi- or tricuspid valve, a ball valve, a valve formed from the myocardium itself, or a valve that opens and closes in response to the contraction and relaxation of the heart muscle, or in response to the electrical signals in the heart.